1. Field of the Invention
The invention relates to a single focus lens system and a photographing apparatus including the single focus lens system.
2. Description of the Related Art
Recently, the use of digital cameras and video cameras including a solid state pickup device such as a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) has considerably increased. In particular, demand for lens interchangeable single reflex cameras is increasing, and common single reflex cameras have been distributed. Digital cameras including an image pickup device such as a CCD or a CMOS, or imaging optical devices such as cameras for use in mobile phones should be manufactured at low cost, have small sizes, and be lightweight.
In addition, as demand for such cameras increases, demand for single focus lenses such as telephoto lenses or wide angle lenses is also increasing. A suggested wide angle lens is a retro-focus type (inverted telephoto type) lens structure including a first lens group having a long back focal length and having a negative refractive power, and a second lens group having a positive refractive power, sequentially arranged in order from an object side.
By using the retro-focus type lens system, a long back focal length and a wide viewing angle may be provided. However, users demand, in addition to high optical performance, a compact lens system, but it is difficult to reduce the size of the retro-focus type lens system.